Nut-tapping machine



Dec. 25, 1951 Filed May 14, 1948 R. NICHOLS ETAL NUT-TAPPING MACHINE 8Sheets-Sheet 1 fiJslzichoZ/s JIBrowIv Dec. 25, 1951 I R. NICHOLS ETAL2,580,187

NUT-TAPPING MACH-INE Filed May 14, 1948 8 Sheets-Sheet 2 f V V k J Fig.2

Impala-toms .132" echo L5 D 9 R. NICHOLS ElAL 2,536,187

NUT-TAPPING MACHINE Filed May 14, 1948 8 SheetsSheet 4 .H .132 (Lek/o L51 12/ van-201 s Dec. 25, 1951 R. NICHOLS EI'AL NUT-TAPPING MACHINE 8Sheets-Sheet 5 Filed May 14, 1948 Dec. 25, 1951 R. NICHOLS ETALNUT-TAPPING MACHINE 8 Sheets-Sheet 6 Filed May 14, 1948 emf/ails ,E zciao Z5 H.231 0 ZUJZ/ 0 Dec. 25, 1951 Filed May 14, 1948 R. NICHOLSEI'AL NUT-TAPPING MACHINE 8 Sheets-Sheet 7 Z22 vzfziiozs 15.. JSZ'zL0110 La ar $1 Q Dec. 25, 1951 Filed May 14, 1948 R. NICHOLS ETALNUT-TAPPING MACHINE 8 SheetLs-Sheet 8 "III/IA which they can be tapped.

Patented Dec. 25, 1951 Rex I Nichols, j- Edgbaston, Birmingham, and

William' Brown;- Kings Heath, Birmingham,

England.

Application May 14, 1948, Serial No. 27,056

In Great Britain June 16, 1947 This invention relates to nut-tappingcession to a rotary and axially movable tap, or

each ofa plurality of such taps, anda're' held against rotation whilethe tap is passing through them-the arrangement being such that thetapped work pieces accumulate on the tap until discharged from theendreinote from the operative end I The primary object'of the inventionis to provide improved means for automatically fee'ding the work piecesto the position or positions in Another-object of the invention isto-render the machine fully automaticin its action. In the accompanyingsheets of explanatory drawings: I

/ Figures 1 and '2 are =respectivelya' side view and 'a front view of atwo-spindleautomatic nuttapping machine embodying the invention.

Figures 3' and 4- are respectively a sectional 1 side View and a frontview of the tap spindles and their actuating means drawn to a largerscale than Figures 1 and 2, Figure 3 being taken on theline 33 of Figure4. Y

' Figure 5 is a sectionalside viewof the workpiece feeding means drawnto the same scale as' taken on the line"5--'5"of" the various partsthereof to'be operated pneumatically.

-Figure 9 is a side view of one of a plurality of similar pneumaticallyoperable slide'ivalves employed in the system illustrated by Figure 8,and Figures 10- and 11 are respectively a sectional view taken on theline |lll0 of Figure 9, and a part sectionalview illustrating theslidableclosure'member'of the valve and its seating.

Figures 12 and 13 aresectional views taken at right angles to each otherof one of a plurality of similar mechanically operable valves employedin-the system illustrated by Figure 8.v 1 A .V

The machine shown in Figures 1 to .7 of the drawingsis provided withapair ofxvertically arranged rotary and axially .movable ,tap spindlesas 1 adapted to be rotated by an electric motor 2 ,throughthe medium ofa belt 3passing; around: pulleys as .4 on the motor spindle and machinesof the kindinwhich work pieces are fed in suc- ,4 Claims. (Cl. 104-139)near the upper endsrof the: tap spindles, the

latter being in'slidable spline connection with r the correspondingpulleys. To the lower ends of the tap spindles l are securedtap-holders, each comprising a hollow. body part 5 having a side opening.6, and a tubular guide 1 depending from the underside of the body part,the guide and body part being adapted to accommodate the stem of a tap 8provided with a curved upper end,

and to permit tapped. work pieces (through which the, operative end ofthetap has passed) to accumulate 0n the stem until they reach its uppercurved end, whereuponthey are flung by centrifugal force oil the stemand through the side opening of thebody part into a surrounding casing 9from which they are delivered by a chute I0. .Such a tap holder and tapare known and do not require further description. The tap spindles I arerotatably supported by ball bearings I] in sleeves I2 which, togetherwith the tap spindles, are vertically slidable in bearings I3 carried byor formed integrally with a plate or bracket I 4, the latter beingsupported on a fixed part of the machine by vertical guides 15, andbeing vertically adjustable by a rotatable but axially immovable stem I6in screw thread engagement with a complementary part I! of the plate orbracket.

In carrying the invention into efiect in the manner shown in thedrawings, we employ for imparting axial movements to the verticallyarranged tap spindles l, a piston 18 which is slidable in a fixedvertical cylinder I9 mounted on a horizontal Web 20 uniting the bearingsIS in which the spindle-supporting sleeves l2 are slidable. The pistonI8 is provided with a rod 2| which extends through the lower end of thecylinder l9 and through the web 20, and which at its lower end carriesan adjustable collar 22.

This collar serves at its upper side to support.

the adjacent ends of a pair of lateral projections 23 respectivelyformed on annular members 24 which are secured to the lower ends of thesleeves I2, and which carry and close the upper ends of the casings 9surrounding the tap holders above described. The adjacent ends of thelateral projections 23 are also shaped to rest one on the other. Thus,the outer end of the right hand projection 23 in Figure 4 rests on theadjacent end of the left hand projection 23. The purpose of this is toprevent downward movement of the tap spindle 1 associated with the righthand projection 23 when downward movement of the other tap spindle isobstructed. The cylinder I9 is provided at its upper and lower .endswith pipe connections 25 through which compressed air can be admitted toand released from the cylinder. Upward movement of the piston l8 underthe action of compressed air admitted to the lower end of the cylinder19 is accompanied by corresponding upward movement of the sleeves I2carrying the tap spindles I, due to the inter: action of the collar 22on the piston-rod 2| and the lateral projections 23' on the annularmembers 24 secured to the sleeves. Downward movement of the piston l8under the action of compressed air admitted to the upper end of' thecylinder allows the sleeves I2 carrying the tap spindles I to descendunder the actionof gravity. During the downward movements of the tapspindles l, the taps 8 act on the work pieces to be tapped, and as thesemovements are efiected under the action of gravity alone, anyobstruction thereto as a result of an inaccuracy in a work pieceoccupying a tapping position will merely cause the descending'tap toibearrested. without breaking or otherwise damaging the tap.

For receiving the work pieces to be tapped, we employ a pair of hoppers26, and in communication with the lower ends of these hoppers we arrangea pair of inclined chutes 21 along which the work pieces can travel insuccession under the action of gravity. In Figure a number-of theworkpieces are shown and indicated by 28. The width of the chutes 21 mayconveniently be made adjustable to suit work pieces a of differentsizes. To facilitate delivery of the work pieces from the hoppers 26 tothe chutes 2'l under the action of gravity, there are mounted on theupper end portions of the chutes relatively slidable agitating plates 29which extend intothe lower ends of the hoppers. Also each chute 2! hasassociated with it a pair of longitudinally arranged bars 30, 3! whichmay be of angle section, and which are mounted on opposite sides of thechute so asto be capable of endwise slidingmovement relatively to thechute, the upper ends of the bars'being situated adjacent to the hopperdelivery openings as 32,

and having their edges obliquely disposed as shown in the directions ofboth their length and breadth to assist in guiding the work pieces fromthe hoppers 26 into theupper ends of the chutes.

The slidable bars- 33, which are situated at the adjacent'sides of thechutes 21, are secured at their upper ends to the agitating plates 29 bybolts 33 or other fastenings. Also the slidable bars 3| areinterconnected near their upper ends by a transverse bar 34 which at itscentre is secured to a piston rod 35, and is'connected through themedium of slotted levers 36 to the I of the piston in the cylinder isaccompanied by opposite reciprocatory movements of the two bars 30, 3!associated with each chute 2'1,- and also'by reciprocation of .theagitating plates 29' which are secured to the bars 30. The plates 29thus serve to agitate the work pieces in the hoppers 2G, and therebypermit free movement of the work pieces from the hoppers to the upperends of the chutes 21, this movement being assisted by the oblique upperends of the bars- 36," 3|. The cylinder 38 is provided with pipeconnections 39 for the admissionand release ofcompressed air. 7 P

The chutes 21 are formed in part or supported by a common inclined plate4|] which at its lower end is supported by a table 4|, and on the tableare mounted guides 42 along which the work pieces 28 leaving the chutescan be fed, horizontally to tapping positions beneath thecorrespondingtaps 8, these positions being determined by adjustablestops 43 on the table. At the ends adjacent to the tapping positions,the guides 42 .are formed with vertical extensions as 42? which serve tohold the work pieces against rotation during the tapping operations.

Arranged in'association with each chute 21 is a feed member 44Jwhich isadapted by succesthechute to impart feeding movements to the precedingwork pieces. Each feed member 44 consists of a radial peg adjustablysecured on a rod 45,and each chute 2'! is formed near its lower end witha centrally arranged'longitudinal slot 46 through which the associatedfeed member can pass into engagement with the hole in the work pieceoccupying an intermediate position in-the chute over the upper endof'the slot. Also each feed member 44 is adapted to receive a compoundreciprocatory motion consisting of a forward movement through the upperend of the associated slot 46 into engagement with the adjacent workpiece, a feeding movement along the slotto propel the said work piecealong the chute and thereby impart a feed movement to the preceding workpieces, a retractive movement out of engagement with the propelling workpiece, and finally an idle return movement to its initial position. Forenabling this motion to be imparted to the feed members 44, the rodscarrying the feedmembersare secured to pistons 41, and the latter areslidable under the action of compressed air in; cylinders 48. which arepivotally attached to fixed supporting brackets '49 on the underside ofthe chute plate 40. Moreover, there is arranged at right angles andadjacent to the tworods carrying the feed members 44, a

third rod 50 which extends between the first mentioned rods and theunderside of the chute plate 40, and which is connected to a piston 5|,the latter being slidable under the action of compressed air in a fixedcylinder 52. The third rod 50' has secured thereon at positions adjacentto the othertwo rods 45, a pair of collars 53 formed-atpositionsintermediate their ends with shoulders 54 of conical form. Further, thetwo rods 45 carrying the feed members-44 are loaded -at the endsremotezfr'om the pistons 41 by any convenient compression or othersprings 55,

' which hold these rods in contact with the collars 53 on the third rod50. i moved-axially in the appropriate direction the collars53'thereonrallow the other two rods 45 to be moved laterally by theirloading springs 55 for'causing movement of the feed members 44 throughthe slots 46 in the chutes 21 into engagementwith the adjacent workpieces 28. The

ensuing feeding movements of the feed members 44 are eflected by axialmovements of the rods 45 carrying the feed members prior to the retum-When the feedmovement ofvthe third rod 50. ing movements have beencompleted the third 'rod 50. is returned to its initial position, and

7 5 The rods 45 are then moved axially in the oppo- When the third rod50 f site direction for effecting the idle return, move-.- mentsof thefeed members 44 'to their:-rinitial= positions inreadiness -for anothercycle of op-' erations;

The cy1inders 48 arei provided at their ends with pipe connections 56for the admission and release of the compressed air required to actuatethe pistons 41 which serve to impart the above describedaxial movementsto the rods 45, Like-,

wise the cylinder 52ris'provided at its ends with pipe connections .51fortheadmission and release of the compressed air required toactuate thepiston 5| which serves to impart the-above described axial movements'tothe rod. 58., 1

To prevent the work pieces 28 from being lifted by the engagementtherewith of the feed members 44, any.;convenient means are provided forretaining the work pieces within the:chutes 21 in the regions of the.slots 46. Inzthe example shown such means comprise thin metal strips 58which extend alongthe open upper sides of the lower parts of the chutes2] and the adjacent ends of the guides 42 on the table 4|. The strips 58are carried by plates-59 having secured thereto adjusting screws 68which engage rotatable but axially immovable nuts 'BI onfixed supportingplates 62. v For automatically controlling the flow of compressed airtoand from the cylinders I9, 38, 48 and 52, we employ thersystemillustrated :diagrammatically-in Figure 8. This system 1 is adapted tobe supplied under.,the control of a main valve 63 with compressed airfrom any convenient source, and includes an adjustable pressure-reducingvalve 64, a j manually-operable starting valve65, three-valves 65,61 and68 (hereinafter termed automatic valves) which are operable by airpressure and serve to control the flow of compressed air to and from thecylinders I9, 38, 48 and 52, three valves 69, I8 and II (herereducingvalve 54 through piping 14, I5 and 15 5 and,also has access; to thethree impulse valves,

69, I8 and 'II through piping 14, 15 16, I'I, I8

and I9 without passing through thepressurereducing valve. The purpose ofthe pressure-re: ducing valve 64 is to enable the cylinders I9, 38; 48and 52 to be supplied with compressed-air (herein termed low-pressureair) at a variable pressure lower than that of the air 1 (herein termedthe high pressure air) employedforactuating the autom'aticvalves 66, 6]and 68. Lowpressure, airleaving the pressurereducing valve 64 has accessthrough piping 88 to the; starting valve 65 and, when the latter isopen, can flow through; piping 8I, 82, 83. 84 and 85 to the'threeautomatic valves 66, Gland 68 which control the 65 fiowfoi uc i to a ehe-c i sW133i,

48 and 52. The-automatic,valve 66 serves to; control the flow oilow-pressure air toand i rom; the cylinder I9, and forthis; purpose is.connecfged; to op s of h l n by inin -t 8.1-; Actuation, oi theautomatic valve 661s efiected by high-pressure air supplied theretothrough piping 88,89 under the control of the impulse valve 69.Theautornatic valve fil serves to contrcl. riefl w i wtp s u e artoenclir m t cylinde'rsl38 and 48; and for this purpose is icorinectedto one end of eachof-zthese cylinders by piping 98, 91, .92 "and 93,andstothegother ends by piping 94, 95, ,96 and.9'|.

air supplied thereto through piping 88 and 99 under the control of theimpulse valve I0. The automatic valve ,68 serves to control the flow oflow-pressure aintov andfrom the cylinder 52,

;and for this purpose is connected; to opposite ends of the cylinderbypipingIflI), IIlI. Actuaj tion of the automaticvalve 68 is effected;by highp s u i s p ed th r r gh in j I02; I 83 under: the control oitheimpulse valve II. The impulse valve 89 is operable by the axialmovements of oneof the tap spindles I, (that surrounded by the 'righthand sleeve I2 in'Fi ure 4) through the medium of a radial arm I84(Figure: 1) on the surrounding sleeve, a vertical stem Illiparrying apair of adjustable collars I86, through the medium or which the stem ismovable axially when the spindle approaches its upper and lowerpositions, and a lever I81 interconnecting the stem and impulse valve69, the

arrangement beingsuch that when the spindle approaches its upper orlower position the arm on the: sleeve serves by contact with thecorresponding collar on" the stem to impart axial movement to the stem'which serves, through the i vmedium of the lever I01, 'to actuatetheimpulse valve 69/ 9 The secondimpuls'e valve' I8 is operable in a.similar manner to the impulse valve 69 by the' axial movements of theother tap spindle I.

The third impulse valve "II is operable by the' transverse bar 34;(Figure 7) through which motion is impartedftojthe' agitating plates 29.

For this purpose'the impulse valve TI is provided with anactuating leverI08 which is pivoted to one end of an axially movable stem I09 carryinga pair of adjustable collars III]. Also one end of thebar 34 is providedwith an extension III e which is adapted by' contact with the collars II8 to'impartmovement from the bar to the stem I09; and thus tofthevalve-actuating lever I88;

.The impulse "valves 69, I8 and II may have any convenientiorm, butpreferably they have thevknown formexemplified in Figures 12 and 13; Thevalve shown'in this example comprises 7 a hollow body part 2- containingan oscillatory closuremember. H3 in slidable contact with a seating II4.The body part II2 is provided with an inlet pipe connection -I I5 forthe admission of compressed air, an air exhaust passage IIB, and a pairof additional pipe connections I]? through which compressedair can flowoutof and back to the interior of the body part under the control of theclosure member II3, the last mentioned pipe connections being incommunica-.

tion respectively with a pair of ports I I8 formed port I I9communicating with the exhaust pas sage, so that in one' extremeposition of the closure member one ofwthe'said pair of portscommunicates with the inletpipe connection and the other with the airexhaust passage, and in the other extreme position of the closure memherthe reverse effect is obtained. The closure member H3 is operable by anarm I20 on the 70 inner end of aspindle I2I which passes through theWall of the body part II2 opposite to the seating I I 4, and which hassecured to its outer end a lever I22 adapted to be actuated'by theappropriate moving part of the; machine, a

spring I I23 being arranged rbetween the arm and Actuation of theautomatic valve 6'! iseffectedz'by high-pressure I in the seating II4 atopposite sides of a third,

assess"! theclosure member for holding. the latterrin tightcontactwithiits seating! I '4 The automatic-valves 6-6, stand Ii8 may'also vnections as I29'throughwhich compressed air I.

can flowput -of and-back to the interior of the body'part' underthe'control of the closure member I25. Only one of the pipe'connections I29is shown-in Figure 9-,- the other being situated at the opposite'sideofthebody part I24. These pipe connections were in communicationrespectively with a pair of ports I30 formed in the seating I26 at,opposite sides of athird port I3I communicating withthe exhaust passage;so that in one extreme position of the closure member one of thesaidpair of ports comm-uni-- cates with the inlet port connection and theother with the air exhaust passage, and in the other extreme position ofthe closure member the reverse effect is obtained. The closure memberI25 is operable by a spindle I32 in asim'ilar' manner to the impulsevalve shown in Figures 12 and 13, and on the outer end of the spindle issecured a double-armed lever I33 which is operable to impart movementto' the closure member I25 'by' a pair of pistons I34, the latter beingslidable in cylinders I35 into and out of which high pressure air foractuating the pistons can flow through pipe connections I36.

The operation of the machine above described is as follows: 7

It will be first assumed that the main valve 63 is open for admittinghigh pressure air to the system, the starting valve 65 is in a closedposition in whichit serves to .release'low-pressure air from the part ofthe system supplied through starting valve, and the tap spindles I arerotating. In this condition the tap spindlesl are in their lowermostpositions due to the efieot of gravity,

and the impulse valve 691s in an extreme position in which the automaticvalve 66 is set for admit-- ting low-pressure air to the'lower end andex hausting the upper end of the cylinder" I-9'; Also, the impulse valveT is in an extreme position which the automatic valve 61 is set foradmitting low-pressure air to the upper ends and exhaust ing thelower'ends of the cylinders 38, 48. More-' over, the impulse valve I Iis in an extreme position in which the automatic valve G'Bis set foradmitting low-pressure air to one end and exhausting the other end ofthe cylinder 52 order to hold the piston in this cylinder in theposition in which the feed members 44 can engage the "adjacent workpieces'in the chutes 2'1. If the starting valve 65 is now opened the tapspindles I will be raised and the feed members 44 will perform theiroperative strokes When the tap spindles I approach their uppermostpositions, the impulse valves 69, I0 will be moved to their oppositeextreme position for enabling high p'res'sure air to move the automaticvalves 66-, 61 into positions in which low-pressure air is admitted tothe upper-end and exhausted from the lower end of the cylinder #9, andis admitted to the lowerends and exhaustedfrom the upper ends of thecylinders, 48. Also the impulse valve 'II will-be moved by thetransverse bar 3 associated with the agitating plates 29 tothe.inpposite\ extreme position tor enablin hignpressme air to movetheautomatic valve I58 intoa'position inz'wh-ic-h the piston in-thecylinder 1 52 is moved by low-pressure air in the directionforinretracting;thel feed members; 14. :The tap spindlesfi now-descendunder the action of gravity for. enablmgi -the;1uzquiredI tappingoperations to t behperformed'onmthe work pieces occupying ,the

tapping positions velvieanwhile, the feed members 44 "perform theiridle/return movements;

thetap spindles: tappro'achtheir lowermost positions and the:feed-membersapproach the end of their return travel, theim pulsevalvesBB, l0 and II are returnedrtotheir initial-positions inreadi Whengnessrfor asether cycle ei oper ationsl 'lf-thesdowmvard movement ofeither of spindles Isis obstructed the machine will be broughtto restautomatically clue to the fact that theimpulse valve I59 will beactuated to keep the mach-ineinmctiom same mam-1 the: foregoingWe--have-describedan applica tremor the invention to a two'-spindlemachine l adaptedto operate on two work pieces simultaneously-,-but it may be applied in essentially the machines, or

Etc other mum-spindle teisinglees'pindle machines. 1

By this invention the desired automatic feeding of the work piecesto atapping'pos-itionor positions-can be effected in a simple andexpeditious-- 1 manner; the duty of the attendant being simply tokeepthe: hoppers loaded with work pieces" Also we are'able'to render-anut-tapping machine of the kind specified, fully automatic.

The invention is not; however, limited to the =.constructional detailsabove described as these maybe variedto suit requirements. Thus,-instead oi employing asingle piston and cylinder for impartingreciproc'atory axial movements to the tap spindles, we may employ aseparate piston andcylinderfer each; tap spindle.- or we may dispense-the pneumatic actuating means above described, and in place thereofemploy mechanically operable actuating --means-.

Having thus described our invention what we" claim asnew and desire tosecureby Letters 1 Patent-is Z I'. A nut-tapping'machine of the typespecified,

comprising in" combination a supply hopper for workpieces-tobetapp'ed,-an inclined chute having its upper end incommunication with said hopper so that work'pieces-'from--the latter canenter andtravel down said chute-under theaction of'gravity, averticallyarrangedrotary and axially movable tap spindle a horizontalguidewhich extends from the lowerend of said chutearid along whichworkpieces are-"movable from the lower end of saidchute to a tappingposition beneath said tap spindle, a feed: member movable into, along,-and out of, anintermediate' part ofsaid chute for successivelypropelling different work piecesin said chute-amt thereby impartingfeedmovements.

to the preceding work pieces, a rod arranged beparting thereto axialmovements with respect to sa d feed chute under theaction of compressedair, a spring acting saidrod and tending'ita impart thereto lateral"movement with respect to;

said f'e'ed chute, a second rod arrangedat right angles and adjacent to"thefirst mentioned rod, a collar provided on saidsec'ond rod toimpartlateral movement- "(5116 first mentionedrod}- tap against the action ofsaid spring in response to axial movement of said second rod in onedirection, and a relatively slidable piston and cylinder operativelyassociated with said second rod for imparting axial movements theretounder the action of compressed air.

2. A nut-tapping machine of the type specified, comprising incombination a supply hopper for work pieces to be tapped, an inclinedchute having its upper end in communication with said hopper so thatwork pieces from the latter can enter and travel down said chute underthe action of gravity, a vertically arranged and axially movable tapspindle, a horizontal guide which extends from the lower end of saidchute and along which work pieces are movable from the lower end of saidchute to a tapping position beneath said tap spindle, a feed membermovable into, along,

' and out of, an intermediate part of said chute for successivelypropelling different work pieces in said chute and thereby impartingfeed movements to the preceding work pieces, actuating means operativelyassociated with said feed member for imparting compound reciprocatorymotion thereto, an agitating plate extending into the lower end of saidhopper, a pair of relatively slidable bars situated longitudinally atopposite sides of said chute with their upper ends adjacent to the lowerend of said hopper, said plate being secured to one of said bars, atransverse member secured to the other of said bars and movablelongitudinally of said chute, anid a lever interconnecting saidtransverse member and the bar to which said plate is secured, so thatmovement of said transverse member is accompanied by opposite slidingmovements of said bars.

3. A nut-tapping machine of the type specified, comprising incombination a supply hopper for work pieces to be tapped, an inclinedchute having its upper'end in communication with said hopper so thatwork pieces from the latter can enter and travel down said chute underthe action of gravity, a vertically arranged and axially movable tapspindle, a horizontal guide which extends from the lower end of saidchute and along which workpieces are movable from the lower end of saidchute to a tapping position beneath said tap spindle, a feed membermovable into, along, and out of, an intermediate part of said chute forsuccessively propelling different work pieces in said chute and therebyimparting feed movements to the preceding work pieces, actuating meansoperatively associated with said feed member for imparting a compoundreciprocatory motion thereto, an agitating plate extending into thelower end of said hopper, a pair of relatively slidable bars situatedlongitudinally at opposite sides of said chute with their upper endsadjacent to the lower end of said hopper, said plate being secured toone of said bars, a transverse member secured to the other of said barsand movable longitudinally of said chute, a relatively slidable pistonand cylinder operatively connected to said transverse member forimparting movement thereto under the action of compressed air, and alever interconnecting said transverse member and the bar to which saidplate is secured, so that movement of said transverse member isaccompanied byopposite sliding movements of said bars.

4. A nut-tapping machine oi the type specified, comprising incombination a supply hopper for work pieces to be tapped, an inclinedchute having its upper end in communication with said hopper so thatwork pieces from the latter can enter and travel down said chute underthe action of gravity, a vertically arranged and axially movable tapspindle, a horizontal guide which extends from the lower end of saidchute and along which work pieces are movable from the lower end of saidchute to a tapping position beneath said tap spindle, a feed membermovable into, along, and out of, an intermediate part of said chute forsuccessively propelling different work pieces in said chute and therebyimparting feed movements to the preceding work pieces, pneumaticallyoperable actuating means operatively associated with said feed memberfor imparting compound reciprocatory motion there'- to, and a pneumaticcontrol system comprising a pressure-reducing valve, compressed airsupply piping connected to the inlet side of said pressure-reducingvalve, a manually operable valve having its inlet side connected to thedelivery side of said pressure-reducing valve, a plurality of controlvalves having their inlet sides connected to the delivery side of saidmanually operable valve and their delivery sides connected to saidpneumatically operable actuating means so that said control valves serveto control the flow of compressed air from said manually operable valveto said pneumatically operable actuating means, said control valveshaving operating means responsive to air pressure, and a plurality ofadditional valves having actuating members arranged to be operated bymoving parts of the machine, said additional valves having their inletsides connected to said compressed air supply piping and their deliverysides connected to the operating means of said control valves, so thatsaid additional valves serve to contro1 communication between saidpiping and operating means.

REX NICHOLS. WILLIAM BROWN.

REFERENCES CITED The following references are of record in the file ofthis patent:

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